With telemetry technology, fish can be tracked over distances of several hundred meters since the individually transmitted coded signals are amplified by a small battery. The only externally recognizable transmitters of this type are
telemetric emitter (Fotos: IfÖ)
radio telemetric emitters with a whip antenna which trails either from the mouth, gills, or belly of a tagged fish. Even if the battery is depleted and the code can no longer be read by an antenna, each emitter has a code printed on it which can be referenced to determine when and where the fish was originally tagged.
If you find a telemetric emitter, please fill out the input form and send the transmitter as described on the page “How to send a tag”.